it's a big number for an 8-year-old company, it confirms that facebook's growth is actually slowing. 9 million fewer people registered with facebook last quarter and 57 million fewer than the first of the year. zuck is not worried. fewer users are signing up, they are the right ones, he says, which brings me to tonight's number, 600 million, the number of facebook's mobile users. remember when he was asked about the future of facebook, he said it's mobile, it's mobile, it's mobile. we looped it for you to hear all 37. he says he knows how to make it happen now. in 2006 when the company passed just 25 million users in all, in addition to the u.s. most came from australia, canada, germany and britain. now facebook users are coming in from where the people are. the future, brazil, india, indonesia, and those countries and china are the competitors.